Step 3.5 Flash (free)

Stepfun chatreasoningtool_use Long

API ID: stepfun/step-3.5-flash

Compare Calculate
Input Price
$0.10
/1M tokens
Output Price
$0.30
/1M tokens

About Step 3.5 Flash (free)

Step is StepFun AI's model series, delivering strong performance on general language tasks. The models excel at conversation, reasoning, and content generation. Step demonstrates StepFun's advancement in language model development. For developers seeking capable AI from StepFun, the series offers reliable performance.

💰
Price Ranking
#697 lowest price among 1240 Chat models

Model Specifications

Context Length
262k
Max Output
66k
Release Date
2026-01-29
Capabilities
chat reasoning tool_use
Input Modalities
text
Output Modalities
text

Best For

  • Complex reasoning, math problems, multi-step logic
  • Conversations, content writing, general assistance

Consider Alternatives For

  • Image understanding (needs vision capability)
  • Simple Q&A (cheaper models available)

💰 Real-World Cost Examples

Estimated monthly costs for common use cases

Personal AI Assistant
$0.14
/month
50 conversations/day, ~500 tokens each
Customer Service Bot
$4.20
/month
1000 tickets/day, ~800 tokens each
Data Analysis Pipeline
$5.85
/month
500 analyses/day, ~2k tokens each
Calculate Your Custom Usage

Stepfun Model Lineup

Compare all models from Stepfun to find the best fit

Model Input Output Context Capabilities
Step 3.5 Flash (free) Current $0.10 $0.30 262k chat reasoning tool_use
Step 3.7 Flash $0.20 $1.15 262k chat reasoning tool_use
View All Stepfun Models →

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🚀 Quick Start

Get started with Step 3.5 Flash (free) API

OpenAI-compatible SDK 
from openai import OpenAI

client = OpenAI(
    base_url="https://api.provider.com/v1",
    api_key="YOUR_API_KEY"
)

response = client.chat.completions.create(
    model="stepfun/step-3.5-flash",
    messages=[
        {"role": "user", "content": "Hello!"}
    ]
)
print(response.choices[0].message.content)

Resources

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